You may be tempted to think that exorcism is an obscure practice relegated to history books and horror movies. But this form of combatting the devil is surprisingly widespread here in america and around the world. What is rare is actually getting to see an exorcism in process. But tonight, abc's bob woodruff takes us deep into the jungles of colombia to meet a man who claims he fights satan full time and for a price. Here is our series "off the map." Reporter: You are about to witness a terrifying but fascinating ritual. Mala, mala. Si, mala. Reporter: A man many believe is blessed with special powers direct from god, battling the demen demon he says has taken over this woman's bed 's body and trying to kill her. An idea made famous in the movies. The ability to fight face to face with the devil. But hollywood's version of "the exorcist" has nothing on this. Because these are not actors. They are real villagers and farmers. Even their young children. Willing to spend an entire month's salary in the hope they will be saved by one of south america's most sought after spiritual leaders. They call him el exorcisto, "the exorcist." To meet him, we travel deep into the andes mountains of western colombia. People have to travel a long way to get here. Hitching a ride with his brother who is a cab driver. All right, this will be interesting to see. I have never in my entire life ever witnessed any kind of exorcism. But first an unexpected stop at a gas station where our translator tries to convince the driver that the car has plenty of fuel for the trip. He said, no, no, no for the fire. I said what fire? The one he puts around the people. Nice to meet you. At the farm he is eager to show us videos of his past work. Oh, no. Roim s Reporter: Services that do not come cheap. He travels $35 for a diagnosis, $230 for an exorcism. As a second generation exorcist he says he battled thousand of demons in the past 25 years. Reporter: What's the worst case you have ever seen? He describes a woman who came to him, cursed to be like a frog. He claims he was able to cure her. But local catholic leaders say it is all an act. They disapprove of the work that he does here. But is it really that far-fetched? Watch this, it is what many believe is pope francis himself performing an exorcism on a wheelchair bound man. It happened earlier this year in rome. Pope francis hold his hand on the man's head for 15 second. While the man shakes and makes strange sound. The vatican downplayed the incident. Many believers say there is no doubt in what they saw. In fact, belief in the power of exorcism is as old as cristian te team -- christianity. It tells of jesus casting off demons. The katrina l the catholic church has an 82 page book, a how to guide of how to get rid of the devil. You saw a witch? What did it look like? claudia is one who has come to brother hermes seeking a cure from what you might call "a messy divorce" she claims her ex-husband had a curse put on her so she would never love another man. But olga says her troubles are far more serious. Reporter: A woman put a -- put a curse on you? Translator: The curse was that she be killed. Reporter: They have been all covered with dirt, lyme, flowers, eggs, wrapped minto their feet. Then a warning that we should all move back. Olga's demon is putting up a fight. As he counts down, she becomes agitated. It is an intense confrontation, lasting more than 20 minutes. Just tell me how you feel. A little bit dizzy. I saw her going like this. She was saying good-bye. Saying good-bye. Rop are you co-- Reporter: Are you better now? Is the evil gone? I'm well. Reporter: There is still work to be done on claudia. That witch's spell keeping her from finding new love. Reporter: Did it work? Do you feel like you got that, that soul out of you? You deeply believe in brother hermes. He is going to go try to save a child now. Inside we fiendnd a young boy and his brother. This time not a dough moemon. A stomach ache. No dock motor has been able to help. Whatever powers he has. We witness this. The boy stops crying. Reporter: He sound like he was trying to get tortured by you. He was crying a lot. It's good. It's good that they cry out. Reporter: Whether you think he is a man of god or just a sly huckster, there is no denying the impact he has on the people here or their belief that this simple man can change their lives. Is there any way you can test me to see if I am possessed by some kind of evil spirit? He says it doesn't work really that way. He says that a person comes who does bad things, you do not have a bad spirit, you have the spirit of god that made you wise, that made you a good journalist, that's your gift. Reporter: Well, thank you. Thank you for that. You know, I'm glad the diagnosis turns out well. Reporter: Before we can get back on the road. The brother shares a secret of his own. He loves that movie. The exorcist. He has been fascinated by it ever since he was a little boy. And says he will produce the next remake. Reporter: You want to be the next exorcist star? Who is going to play you in the movie? He is going to be himself. Reporter: No george clooney, no tom cruise? Translator: He says they're going to go fade away. That's when I come in. Reporter: We can't wait to see your movie. Bob woodruff for "nightline" in colombia.

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